Using DialogFragments in Android

MainActivity.java :

public class MainActivity extends FragmentActivity {
     @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FragmentManager fm = getSupportFragmentManager();
        dialogfragment testDialog = new dialogfragment();
        testDialog.setRetainInstance(true);
        testDialog.show(fm, "fragment_name");
    }}

Dialogfragment.java :

public class Dialogfragment extends DialogFragment {    
    public void TestDialog() {
        // Empty constructor required for DialogFragment
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.dialog, container);
        return view;
    } }

dialog.xml :

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/edit_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:orientation="vertical"> 
       <TextView
            android:id="@+id/lbl_your_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello from Mark's Playground, DialogFragment Demo"/> 
</LinearLayout>